Calculation of Compound Interest:

To calculate the compound interest, we need to use the formula:

A = P(1 + r/n)^(nt)

Where:
A = the final amount after the interest has been compounded
P = the principal amount (initial investment)
r = the annual interest rate (in decimal form)
n = the number of times that interest is compounded per year
t = the number of years

In this case, we have:
P = Rs. 2000
r = 5% per annum (or 0.05 in decimal form)
n = 1 (interest compounded annually)
t = 3 years

Calculation:

Substituting the values into the formula, we get:

A = 2000(1 + 0.05/1)^(1*3)
= 2000(1 + 0.05)^3
= 2000(1.05)^3
= 2000(1.157625)
= Rs. 2315.25 (rounded to two decimal places)

So, the final amount after 3 years would be Rs. 2315.25.

Calculation of Compound Interest:

To calculate the compound interest, we subtract the principal amount from the final amount:

Compound Interest = Final Amount - Principal Amount
= Rs. 2315.25 - Rs. 2000
= Rs. 315.25 (rounded to two decimal places)

Therefore, the compound interest on Rs. 2000 at 5% per annum for 3 years is Rs. 315.25.

Summary:

Principal Amount (P) = Rs. 2000
Annual Interest Rate (r) = 5%
Number of Times Compounded per Year (n) = 1
Number of Years (t) = 3

Using the compound interest formula, we calculated the final amount after 3 years to be Rs. 2315.25 and the compound interest to be Rs. 315.25.